I live on a super busy road in the forest. we have pretty good traffic. im trying to save 400 bucks asap. could you list some ideas on how to make fast cash? btw im under 16 and cant babysit.

If you have an area you can walk or bike to reach your neighbors, or get dropped off in a large neighborhood and offer services such as:
Mow lawns and pull weeds from gardens.
Offer a window washing service.
Minor repairs if you are adept.
Ask your parents what you could do for them to earn some extra cash.
Are you good at anything in particular? Put those skills to use. For instance, if you are good at drawing or painting, try selling them online (if you are allowed) or at a consignment shop.
I know you said you can’t babysit, if you are good at any school subjects though, can you tutor?
If there are any horse barns around, ask if you can clean the stalls out and keep their barn clean, etc.